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by Harold_V
Fri Oct 30, 2020 3:05 pm
Forum: General Discussion
Topic: Why would industry use undersized taps?
Replies: 17
Views: 377

Re: Why would industry use undersized taps?

Yep! Bastard threads have been used for that purpose by many manufacturers. I make it a policy to avoid doing business with them, as they are inclined to rape the consumer. I was shocked to read that the undersize of the taps in question is so great. Far beyond anything one would use for interferenc...
by Harold_V
Fri Oct 30, 2020 3:02 pm
Forum: Buy, Sell, Trade, Wanted, Free!
Topic: FS 6" 3 Jaw chuck flat back
Replies: 2
Views: 10

Re: FS 6" 3 Jaw chuck flat back

A perfect opportunity for those who wish to start using soft jaws.

H
by Harold_V
Fri Oct 30, 2020 3:10 am
Forum: General Discussion
Topic: Why would industry use undersized taps?
Replies: 17
Views: 377

Re: Why would industry use undersized taps?

Yep! I dare say that the size of a tap goes unchanged by the time it has dulled beyond being useful. That might not be true if a guy is tapping blocks of aluminum oxide, however. :wink: Now, I must say I had seen an awful lot of oddities over the many years I was in the railroad supply business, bu...
by Harold_V
Fri Oct 30, 2020 2:08 am
Forum: General Discussion
Topic: Why would industry use undersized taps?
Replies: 17
Views: 377

Re: Why would industry use undersized taps?

No. Pitch diameter is independent of both of those features. Look at it as the depth of the cutting tool, but measured at the pitch line. When the flat of the cutting tool is correct, the minor diameter (for an A, or external thread) will automatically be in tolerance when the pitch diameter is corr...
by Harold_V
Fri Oct 30, 2020 1:53 am
Forum: The Junk Drawer
Topic: Sirens
Replies: 6
Views: 144

Re: Sirens

I think I know what you're talking about, and if I'm right, you're cruising for a bruising. I just can't help but think that you're discussing a political issue, something that is going to get you banned from the board if you persist. If I am wrong, please accept my apology. If I'm right, cease and ...
by Harold_V
Thu Oct 29, 2020 3:09 pm
Forum: General Discussion
Topic: Why would industry use undersized taps?
Replies: 17
Views: 377

Re: Why would industry use undersized taps?

As I recall, the company purchased standard "gun" taps which the tool room ground very slightly undersize, producing a thread with a major diameter slightly smaller than nominal. I once by accident used one of those taps to tap a hole into a fixture I was building. Imagine my puzzlement when I disc...
by Harold_V
Thu Oct 29, 2020 2:56 pm
Forum: General Discussion
Topic: need help with Sajo mill
Replies: 3
Views: 1207

Re: need help with Sajo mill

Ampersand,
Welcome to the board.
As the OP has not made a showing on the board in more than a year, I suspect you won't hear from him.

H
by Harold_V
Thu Oct 29, 2020 1:17 am
Forum: 3-in-1 Metalworking Machines
Topic: Need help identifying feed screw threads on Smithy AT-300
Replies: 19
Views: 392

Re: Need help identifying feed screw threads on Smithy AT-300

Yes, there were accurate screws. They were created by thread grinders, not lathes. Moore used to hand lap their screws to achieve a level of precision that boggled the mind. If memory serves, they were accurate to something like .000020" over 12". Please correct me if I'm wrong, as I'm trusting to m...
by Harold_V
Wed Oct 28, 2020 1:28 am
Forum: General Discussion
Topic: Why would industry use undersized taps?
Replies: 17
Views: 377

Re: Why would industry use undersized taps?

tornitore45 wrote:
Tue Oct 27, 2020 7:27 pm
They were worn out. Of course they were undersized.
Taps get dull long before they wear undersized.
Yep! I dare say that the size of a tap goes unchanged by the time it has dulled beyond being useful. That might not be true if a guy is tapping blocks of aluminum oxide, however. :wink:

H
by Harold_V
Tue Oct 27, 2020 3:52 pm
Forum: The Photo Album
Topic: Jib crane hook modification
Replies: 6
Views: 166

Re: Jib crane hook modification

oooo ! Harold, Can you do a thread on how you made those sweet soft jaws for holding the pipe ? They look like they're cast ? Interestingly, my original intention was to do a post about the soft jaws, not their purpose. Then I figured it might be interesting for others to see how I solved the puzzl...
by Harold_V
Sat Oct 24, 2020 4:15 am
Forum: Build Log
Topic: USATC S-160 Consolidation
Replies: 79
Views: 53320

Re: USATC S-160 Consolidation

Very nice, Dick.

H
by Harold_V
Fri Oct 23, 2020 1:31 am
Forum: Build Log
Topic: USATC S-160 Consolidation
Replies: 79
Views: 53320

Re: USATC S-160 Consolidation

Sandiapaul wrote:
Thu Oct 22, 2020 7:28 pm
Thanks...and well I hadn't had my coffee yet Harold!
Chuckle!
Trust me, I understand. I make more than my share of errors like that. We're all human and prone to doing so.
No offense intended, I hope you know. :wink:

H